Biology Reference
In-Depth Information
the Mekong River. However, the present distribution and current population
status of long-tailed macaques are not known.
Primate fauna is rich in southern-most Laos, which includes prosimians (i.e.,
lorises), cercopithecids, colobines, and lesser apes (i.e., gibbons) (Duckworth
et al
.,
1999
). Laos contains highly endangered species, such as red-shanked
douc langurs (
Pygathrix nemaeus
) and yellow-cheeked gibbons (
Nomascus
leucogenys gabriellae
; Duckworth
et al
.,
1999
), as well as typically com-
mon monkeys such as the rhesus (
Macaca mulatta
) and long-tailed macaque
(
M. fascicularis
). All non-human primates in Laos are currently under threat
of extinction because their habitats have been lost to commercial logging,
hydraulic power development, and agriculture, all of which have been driven
by increases in human population, economical development dependent on nat-
ural resources, and foreign capital (Duckworth
et al
.,
1999
). Hunting pressure
on non-human primates, although banned by regulation (i.e., Decree of the
Council of Ministers N185/CCM, 21 October 1986), is still high for foods,
trading, and pest control against agricultural crops (Hamada pers. observation).
If this situation continues unchecked, non-human primate populations will be
locally or entirely exterminated. To ensure their sustainability, their distribu-
tion and diversity should be studied and delineated.
Five species of macaques are distributed in southern Laos, and they have
shared habitats by utilizing different ecological strategies, e.g., use of forest
types (broad-leaf evergreen forest vs. others) and arboreality vs. terrestrial-
ity (Fooden,
1982
). Long-tailed macaques range widely throughout Southeast
Asia (Fooden,
1995
) and appear tough and adaptable to various conditions.
Their exact phylogeographic histories have not yet been elucidated, but they
are important components in their natural eco-systems. Long-tailed macaques
are thought to ecologically compete with rhesus macaques because they belong
to the same species group (
fascicularis
group) (Fooden,
1976
), share similar
biological characteristics, are phylogenetically closely related, and therefore
have overlapping biological needs. In this study, we sought to investigate how
they are distributed and assessed the degree of their interspecific competition.
The region of overlap between these two species was reported to occur
between 15˚N and 20˚N (Fooden,
1995
,
2000
), although the region of overlap
has never been assessed well in Laos. It is also difficult to document past distri-
bution patterns of the two species to reconstruct their level of historical overlap
and how environmental changes might have affected it (e.g., the flowing course
of the Mekong River (Meijaard and Groves,
2006
) the climates of glacier and
inter-glacier alterations in Plio-Pleistocene).
It is well documented that hybridization between long-tailed and rhesus
macaques occurs in the eastern half of the Indochinese Peninsula, includ-
ing Laos (Fooden,
1964
,
1995
,
2000
; Tosi
et al
.,
2002
; Hamada
et al
.,
2006
,
